drivers/s390/char/vmwatchdog.c - kernel/msm - Gitiles

 /*
  * Watchdog implementation based on z/VM Watchdog Timer API
  *
  * Copyright IBM Corp. 2004,2009
  *
  * The user space watchdog daemon can use this driver as
  * /dev/vmwatchdog to have z/VM execute the specified CP
  * command when the timeout expires. The default command is
  * "IPL", which which cause an immediate reboot.
  */
 #define KMSG_COMPONENT "vmwatchdog"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
 #include <linux/watchdog.h>

 #include <asm/ebcdic.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>

 #define MAX_CMDLEN 240
 #define MIN_INTERVAL 15
 static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
 static int vmwdt_conceal;

 static int vmwdt_nowayout = WATCHDOG_NOWAYOUT;

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
 MODULE_DESCRIPTION("z/VM Watchdog Timer");
 module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
 MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
 module_param_named(conceal, vmwdt_conceal, bool, 0644);
 MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
 		" is active");
 module_param_named(nowayout, vmwdt_nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
 		" (default=CONFIG_WATCHDOG_NOWAYOUT)");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

 static unsigned int vmwdt_interval = 60;
 static unsigned long vmwdt_is_open;
 static int vmwdt_expect_close;

 static DEFINE_MUTEX(vmwdt_mutex);

 #define VMWDT_OPEN	0	/* devnode is open or suspend in progress */
 #define VMWDT_RUNNING	1	/* The watchdog is armed */

 enum vmwdt_func {
 	/* function codes */
 	wdt_init   = 0,
 	wdt_change = 1,
 	wdt_cancel = 2,
 	/* flags */
 	wdt_conceal = 0x80000000,
 };

 static int __diag288(enum vmwdt_func func, unsigned int timeout,
 			    char *cmd, size_t len)
 {
 	register unsigned long __func asm("2") = func;
 	register unsigned long __timeout asm("3") = timeout;
 	register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
 	register unsigned long __cmdl asm("5") = len;
 	int err;

 	err = -EINVAL;
 	asm volatile(
 		"	diag	%1,%3,0x288\n"
 		"0:	la	%0,0\n"
 		"1:\n"
 		EX_TABLE(0b,1b)
 		: "+d" (err) : "d"(__func), "d"(__timeout),
 		  "d"(__cmdp), "d"(__cmdl) : "1", "cc");
 	return err;
 }

 static int vmwdt_keepalive(void)
 {
 	/* we allocate new memory every time to avoid having
 	 * to track the state. static allocation is not an
 	 * option since that might not be contiguous in real
 	 * storage in case of a modular build */
 	static char *ebc_cmd;
 	size_t len;
 	int ret;
 	unsigned int func;

 	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
 	if (!ebc_cmd)
 		return -ENOMEM;

 	len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
 	ASCEBC(ebc_cmd, MAX_CMDLEN);
 	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);

 	func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
 	set_bit(VMWDT_RUNNING, &vmwdt_is_open);
 	ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
 	WARN_ON(ret != 0);
 	kfree(ebc_cmd);
 	return ret;
 }

 static int vmwdt_disable(void)
 {
 	int ret = __diag288(wdt_cancel, 0, "", 0);
 	WARN_ON(ret != 0);
 	clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
 	return ret;
 }

 static int __init vmwdt_probe(void)
 {
 	/* there is no real way to see if the watchdog is supported,
 	 * so we try initializing it with a NOP command ("BEGIN")
 	 * that won't cause any harm even if the following disable
 	 * fails for some reason */
 	static char __initdata ebc_begin[] = {
 		194, 197, 199, 201, 213
 	};
 	if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
 		return -EINVAL;
 	return vmwdt_disable();
 }

 static int vmwdt_open(struct inode *i, struct file *f)
 {
 	int ret;
 	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open))
 		return -EBUSY;
 	ret = vmwdt_keepalive();
 	if (ret)
 		clear_bit(VMWDT_OPEN, &vmwdt_is_open);
 	return ret ? ret : nonseekable_open(i, f);
 }

 static int vmwdt_close(struct inode *i, struct file *f)
 {
 	if (vmwdt_expect_close == 42)
 		vmwdt_disable();
 	vmwdt_expect_close = 0;
 	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
 	return 0;
 }

 static struct watchdog_info vmwdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 	.firmware_version = 0,
 	.identity = "z/VM Watchdog Timer",
 };

 static int __vmwdt_ioctl(unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		if (copy_to_user((void __user *)arg, &vmwdt_info,
 					sizeof(vmwdt_info)))
 			return -EFAULT;
 		return 0;
 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, (int __user *)arg);
 	case WDIOC_GETTEMP:
 		return -EINVAL;
 	case WDIOC_SETOPTIONS:
 		{
 			int options, ret;
 			if (get_user(options, (int __user *)arg))
 				return -EFAULT;
 			ret = -EINVAL;
 			if (options & WDIOS_DISABLECARD) {
 				ret = vmwdt_disable();
 				if (ret)
 					return ret;
 			}
 			if (options & WDIOS_ENABLECARD) {
 				ret = vmwdt_keepalive();
 			}
 			return ret;
 		}
 	case WDIOC_GETTIMEOUT:
 		return put_user(vmwdt_interval, (int __user *)arg);
 	case WDIOC_SETTIMEOUT:
 		{
 			int interval;
 			if (get_user(interval, (int __user *)arg))
 				return -EFAULT;
 			if (interval < MIN_INTERVAL)
 				return -EINVAL;
 			vmwdt_interval = interval;
 		}
 		return vmwdt_keepalive();
 	case WDIOC_KEEPALIVE:
 		return vmwdt_keepalive();
 	}
 	return -EINVAL;
 }

 static long vmwdt_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 {
 	int rc;

 	mutex_lock(&vmwdt_mutex);
 	rc = __vmwdt_ioctl(cmd, arg);
 	mutex_unlock(&vmwdt_mutex);
 	return (long) rc;
 }

 static ssize_t vmwdt_write(struct file *f, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
 	if(count) {
 		if (!vmwdt_nowayout) {
 			size_t i;

 			/* note: just in case someone wrote the magic character
 			 * five months ago... */
 			vmwdt_expect_close = 0;

 			for (i = 0; i != count; i++) {
 				char c;
 				if (get_user(c, buf+i))
 					return -EFAULT;
 				if (c == 'V')
 					vmwdt_expect_close = 42;
 			}
 		}
 		/* someone wrote to us, we should restart timer */
 		vmwdt_keepalive();
 	}
 	return count;
 }

 static int vmwdt_resume(void)
 {
 	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
 	return NOTIFY_DONE;
 }

 /*
  * It makes no sense to go into suspend while the watchdog is running.
  * Depending on the memory size, the watchdog might trigger, while we
  * are still saving the memory.
  * We reuse the open flag to ensure that suspend and watchdog open are
  * exclusive operations
  */
 static int vmwdt_suspend(void)
 {
 	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
 		pr_err("The system cannot be suspended while the watchdog"
 			" is in use\n");
 		return NOTIFY_BAD;
 	}
 	if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
 		clear_bit(VMWDT_OPEN, &vmwdt_is_open);
 		pr_err("The system cannot be suspended while the watchdog"
 			" is running\n");
 		return NOTIFY_BAD;
 	}
 	return NOTIFY_DONE;
 }

 /*
  * This function is called for suspend and resume.
  */
 static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
 			     void *ptr)
 {
 	switch (event) {
 	case PM_POST_HIBERNATION:
 	case PM_POST_SUSPEND:
 		return vmwdt_resume();
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
 		return vmwdt_suspend();
 	default:
 		return NOTIFY_DONE;
 	}
 }

 static struct notifier_block vmwdt_power_notifier = {
 	.notifier_call = vmwdt_power_event,
 };

 static const struct file_operations vmwdt_fops = {
 	.open    = &vmwdt_open,
 	.release = &vmwdt_close,
 	.unlocked_ioctl = &vmwdt_ioctl,
 	.write   = &vmwdt_write,
 	.owner   = THIS_MODULE,
 	.llseek  = noop_llseek,
 };

 static struct miscdevice vmwdt_dev = {
 	.minor      = WATCHDOG_MINOR,
 	.name       = "watchdog",
 	.fops       = &vmwdt_fops,
 };

 static int __init vmwdt_init(void)
 {
 	int ret;

 	ret = vmwdt_probe();
 	if (ret)
 		return ret;
 	ret = register_pm_notifier(&vmwdt_power_notifier);
 	if (ret)
 		return ret;
 	/*
 	 * misc_register() has to be the last action in module_init(), because
 	 * file operations will be available right after this.
 	 */
 	ret = misc_register(&vmwdt_dev);
 	if (ret) {
 		unregister_pm_notifier(&vmwdt_power_notifier);
 		return ret;
 	}
 	return 0;
 }
 module_init(vmwdt_init);

 static void __exit vmwdt_exit(void)
 {
 	unregister_pm_notifier(&vmwdt_power_notifier);
 	misc_deregister(&vmwdt_dev);
 }
 module_exit(vmwdt_exit);
	/*
	* Watchdog implementation based on z/VM Watchdog Timer API
	*
	* Copyright IBM Corp. 2004,2009
	*
	* The user space watchdog daemon can use this driver as
	* /dev/vmwatchdog to have z/VM execute the specified CP
	* command when the timeout expires. The default command is
	* "IPL", which which cause an immediate reboot.
	*/
	#define KMSG_COMPONENT "vmwatchdog"
	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

	#include <linux/init.h>
	#include <linux/fs.h>
	#include <linux/kernel.h>
	#include <linux/miscdevice.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/slab.h>
	#include <linux/suspend.h>
	#include <linux/watchdog.h>

	#include <asm/ebcdic.h>
	#include <asm/io.h>
	#include <asm/uaccess.h>

	#define MAX_CMDLEN 240
	#define MIN_INTERVAL 15
	static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
	static int vmwdt_conceal;

	static int vmwdt_nowayout = WATCHDOG_NOWAYOUT;

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
	MODULE_DESCRIPTION("z/VM Watchdog Timer");
	module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
	MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
	module_param_named(conceal, vmwdt_conceal, bool, 0644);
	MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
	" is active");
	module_param_named(nowayout, vmwdt_nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
	" (default=CONFIG_WATCHDOG_NOWAYOUT)");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

	static unsigned int vmwdt_interval = 60;
	static unsigned long vmwdt_is_open;
	static int vmwdt_expect_close;

	static DEFINE_MUTEX(vmwdt_mutex);

	#define VMWDT_OPEN 0 /* devnode is open or suspend in progress */
	#define VMWDT_RUNNING 1 /* The watchdog is armed */

	enum vmwdt_func {
	/* function codes */
	wdt_init = 0,
	wdt_change = 1,
	wdt_cancel = 2,
	/* flags */
	wdt_conceal = 0x80000000,
	};

	static int __diag288(enum vmwdt_func func, unsigned int timeout,
	char *cmd, size_t len)
	{
	register unsigned long __func asm("2") = func;
	register unsigned long __timeout asm("3") = timeout;
	register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
	register unsigned long __cmdl asm("5") = len;
	int err;

	err = -EINVAL;
	asm volatile(
	" diag %1,%3,0x288\n"
	"0: la %0,0\n"
	"1:\n"
	EX_TABLE(0b,1b)
	: "+d" (err) : "d"(__func), "d"(__timeout),
	"d"(__cmdp), "d"(__cmdl) : "1", "cc");
	return err;
	}

	static int vmwdt_keepalive(void)
	{
	/* we allocate new memory every time to avoid having
	* to track the state. static allocation is not an
	* option since that might not be contiguous in real
	* storage in case of a modular build */
	static char *ebc_cmd;
	size_t len;
	int ret;
	unsigned int func;

	ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
	if (!ebc_cmd)
	return -ENOMEM;

	len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
	ASCEBC(ebc_cmd, MAX_CMDLEN);
	EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);

	func = vmwdt_conceal ? (wdt_init \| wdt_conceal) : wdt_init;
	set_bit(VMWDT_RUNNING, &vmwdt_is_open);
	ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
	WARN_ON(ret != 0);
	kfree(ebc_cmd);
	return ret;
	}

	static int vmwdt_disable(void)
	{
	int ret = __diag288(wdt_cancel, 0, "", 0);
	WARN_ON(ret != 0);
	clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
	return ret;
	}

	static int __init vmwdt_probe(void)
	{
	/* there is no real way to see if the watchdog is supported,
	* so we try initializing it with a NOP command ("BEGIN")
	* that won't cause any harm even if the following disable
	* fails for some reason */
	static char __initdata ebc_begin[] = {
	194, 197, 199, 201, 213
	};
	if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
	return -EINVAL;
	return vmwdt_disable();
	}

	static int vmwdt_open(struct inode i, struct file f)
	{
	int ret;
	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open))
	return -EBUSY;
	ret = vmwdt_keepalive();
	if (ret)
	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
	return ret ? ret : nonseekable_open(i, f);
	}

	static int vmwdt_close(struct inode i, struct file f)
	{
	if (vmwdt_expect_close == 42)
	vmwdt_disable();
	vmwdt_expect_close = 0;
	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
	return 0;
	}

	static struct watchdog_info vmwdt_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	.firmware_version = 0,
	.identity = "z/VM Watchdog Timer",
	};

	static int __vmwdt_ioctl(unsigned int cmd, unsigned long arg)
	{
	switch (cmd) {
	case WDIOC_GETSUPPORT:
	if (copy_to_user((void __user *)arg, &vmwdt_info,
	sizeof(vmwdt_info)))
	return -EFAULT;
	return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, (int __user *)arg);
	case WDIOC_GETTEMP:
	return -EINVAL;
	case WDIOC_SETOPTIONS:
	{
	int options, ret;
	if (get_user(options, (int __user *)arg))
	return -EFAULT;
	ret = -EINVAL;
	if (options & WDIOS_DISABLECARD) {
	ret = vmwdt_disable();
	if (ret)
	return ret;
	}
	if (options & WDIOS_ENABLECARD) {
	ret = vmwdt_keepalive();
	}
	return ret;
	}
	case WDIOC_GETTIMEOUT:
	return put_user(vmwdt_interval, (int __user *)arg);
	case WDIOC_SETTIMEOUT:
	{
	int interval;
	if (get_user(interval, (int __user *)arg))
	return -EFAULT;
	if (interval < MIN_INTERVAL)
	return -EINVAL;
	vmwdt_interval = interval;
	}
	return vmwdt_keepalive();
	case WDIOC_KEEPALIVE:
	return vmwdt_keepalive();
	}
	return -EINVAL;
	}

	static long vmwdt_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
	{
	int rc;

	mutex_lock(&vmwdt_mutex);
	rc = __vmwdt_ioctl(cmd, arg);
	mutex_unlock(&vmwdt_mutex);
	return (long) rc;
	}

	static ssize_t vmwdt_write(struct file f, const char __user buf,
	size_t count, loff_t *ppos)
	{
	if(count) {
	if (!vmwdt_nowayout) {
	size_t i;

	/* note: just in case someone wrote the magic character
	* five months ago... */
	vmwdt_expect_close = 0;

	for (i = 0; i != count; i++) {
	char c;
	if (get_user(c, buf+i))
	return -EFAULT;
	if (c == 'V')
	vmwdt_expect_close = 42;
	}
	}
	/* someone wrote to us, we should restart timer */
	vmwdt_keepalive();
	}
	return count;
	}

	static int vmwdt_resume(void)
	{
	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
	return NOTIFY_DONE;
	}

	/*
	* It makes no sense to go into suspend while the watchdog is running.
	* Depending on the memory size, the watchdog might trigger, while we
	* are still saving the memory.
	* We reuse the open flag to ensure that suspend and watchdog open are
	* exclusive operations
	*/
	static int vmwdt_suspend(void)
	{
	if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
	pr_err("The system cannot be suspended while the watchdog"
	" is in use\n");
	return NOTIFY_BAD;
	}
	if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
	clear_bit(VMWDT_OPEN, &vmwdt_is_open);
	pr_err("The system cannot be suspended while the watchdog"
	" is running\n");
	return NOTIFY_BAD;
	}
	return NOTIFY_DONE;
	}

	/*
	* This function is called for suspend and resume.
	*/
	static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
	void *ptr)
	{
	switch (event) {
	case PM_POST_HIBERNATION:
	case PM_POST_SUSPEND:
	return vmwdt_resume();
	case PM_HIBERNATION_PREPARE:
	case PM_SUSPEND_PREPARE:
	return vmwdt_suspend();
	default:
	return NOTIFY_DONE;
	}
	}

	static struct notifier_block vmwdt_power_notifier = {
	.notifier_call = vmwdt_power_event,
	};

	static const struct file_operations vmwdt_fops = {
	.open = &vmwdt_open,
	.release = &vmwdt_close,
	.unlocked_ioctl = &vmwdt_ioctl,
	.write = &vmwdt_write,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	};

	static struct miscdevice vmwdt_dev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &vmwdt_fops,
	};

	static int __init vmwdt_init(void)
	{
	int ret;

	ret = vmwdt_probe();
	if (ret)
	return ret;
	ret = register_pm_notifier(&vmwdt_power_notifier);
	if (ret)
	return ret;
	/*
	* misc_register() has to be the last action in module_init(), because
	* file operations will be available right after this.
	*/
	ret = misc_register(&vmwdt_dev);
	if (ret) {
	unregister_pm_notifier(&vmwdt_power_notifier);
	return ret;
	}
	return 0;
	}
	module_init(vmwdt_init);

	static void __exit vmwdt_exit(void)
	{
	unregister_pm_notifier(&vmwdt_power_notifier);
	misc_deregister(&vmwdt_dev);
	}
	module_exit(vmwdt_exit);